80 Flow temperature T10 at DHW in °C (using cylinder thermostat) (if
The P190 error code on Atag boilers indicates 80 flow temperature t10 at dhw in °c (using cylinder thermostat) (if.
Atag P190 means: 80 flow temperature t10 at dhw in °c (using cylinder thermostat) (if. The usual causes are flow temperature t10 at dhw in °c (using cylinder thermostat) (if p100 > 0) or 10-90. You can safely reset the boiler once — if P190 returns, do not keep resetting. A qualified heating engineer should diagnose the root cause.
What Does P190 Mean
The P190 code is shown by the boiler’s control board when it detects 80 flow temperature t10 at dhw in °c (using cylinder thermostat) (if. The boiler then stops instead of continuing to run in that condition: the code is the appliance reporting a problem, not proof that the boiler is broken.
| What you see on the boiler |
|---|
| The display shows P190 and the boiler stops until the fault is cleared |
Common Causes
Causes documented in 2 technical sources.
| Cause |
|---|
| Flow temperature T10 at DHW in °C (using cylinder thermostat) (if P100 > 0) |
| 10-90 |
Safety Warning
P190 involves electrical or pressure-related components. Do not attempt repairs without proper qualifications. Ensure the boiler is electrically isolated before any inspection. If you notice water leaks, unusual sounds, or pressure anomalies, contact a qualified heating engineer immediately.
Parts & Prices
Prices shown are indicative. Actual prices and availability vary by region.
Step-by-Step Diagnosis
Identify which sensor is faulty from the error code (flow, return, DHW, flue gas, or outdoor)
Check the wiring — inspect the connections at both the sensor and the PCB for corrosion or loose terminals
Measure the sensor resistance with a multimeter — compare with the manufacturer's resistance/temperature chart (typically 10kΩ at 25°C (77 °F) for NTC sensors)
If resistance is out of range (infinite = open circuit, near zero = short circuit), replace the sensor
If resistance is correct, check the wiring continuity between the sensor and PCB
If wiring is good, test the PCB input
How to Fix It
Power cycle the boiler (off for 30 seconds, then on)
repair loose connections
if the PCB shows signs of water damage or burnt components, replace the PCB
ensure the replacement PCB is the correct version for the boiler model
after PCB replacement, the boiler may need recommissioning and parameter setup
Refer to the Atag service documentation for the detailed procedure. Only a qualified engineer should carry out these repairs.
Diagnostic Tools
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Affected Models
Atag models that can display fault code P190:
| Model Family | Output Range | Frequency |
|---|---|---|
| All Atag models | — | Possible |
Frequently Asked Questions
Power cycle the boiler (off for 30 seconds, then on). According to the technical documentation, this is the first check on the list for P190.
P190 is not classified as a high-severity fault, so the boiler can be reset once. If P190 comes back, stop resetting: the underlying cause is still there and needs a qualified heating engineer.